The invention relates to a crosscutter for web materials, particularly paper.
DE-U-89 00 516 discloses a crosscutter for corrugated paper or board, which has a cutter block in the form of a composite carbon fibre material tube, to which is fitted by means of screws a cutter beam or support. Bearing and driving take place by means of metallic bearing stubs, which are incorporated into the tube.
DE-A-195 45 003 discloses a cutter shaft, which has an outer shell of a hollow metal section, particularly aluminium and which passes round an inner shell of a composite fibre material, where the cutter beam is constructed in the outer shell. For bearing and mounting purposes shaft journals are fixed in torsionally and fluxurally stiff manner.
In order to be able to cut different formats or sizes with crosscutters and without changing the cutter shaft, it is e.g. known from DE-C-36 08 111 to nonuniformly drive the cutter shafts using unbalance gears or preferably controllable electric motors with high accelerating and decelerating moments. The speed of the cutter shafts is decelerated during a revolution for cutting a format longer than the synchronous format determined by the circumference of the cutter shafts and at the time of cutting is reaccelerated to the web speed. It is also possible by periodic acceleration to a circumferential speed above the web speed to cut formats shorter than the synchronous format. The angle values of the requisite cut lengths and the possible accelerating and decelerating values determine the synchronous cut length, i.e. the cutter shaft diameter.